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There are benefits to prenatal yoga, but lingering questions remain

Studies have found prenatal yoga can offer intriguing benefits. But the body of evidence needs more rigorous research added to it, scientists say.

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Pregnant women are on the receiving end of a long to-do list when it comes to maintaining their own health and that of their fetus. Don’t lift too much, eat this, drink that, lie or sit this way for too long. Exercise is on that list of orders, too. Pregnant women without certain complications are encouraged to exercise, but anyone watching their midsection slowly obscure their toes will tell you that the types of exercise you can and want to do winnow as pregnancy progresses.

During my first pregnancy, I got tired of just walking. Without a gym membership, I wasn’t keen on water aerobics. Lifting weights was never my thing. So midway through I found myself attending a prenatal yoga class. Immediately I felt I was on to something good: My brain and body felt better after the breathing exercises, meditation and stretches that are tailored for pregnant women.

I had some reservations about a few of the poses: Was it OK to lie on my back or do a downward-facing dog? There’s still some debate over whether it’s safe for pregnant women to do these things, and, at the time — in 2015 — studies on prenatal yoga were just starting to emerge in some number.

A little digging into the research shows that most pregnant women would be wise to consider prenatal yoga. The studies find numerous and varied benefits. But researchers caution that more studies that meet more rigorous standards need to be conducted.

One finding, not surprisingly, is that the practice can lessen physical pain, including in the lower back, a particularly hard-hit area of the body during pregnancy. Multiple studies have also shown that prenatal yoga may help alleviate mood disorders such as anxiety and depression. That’s an important finding, considering that close to a quarter of women may experience depression during pregnancy.

But the content of a prenatal yoga class seems to make a difference when it comes to depression, reported a 2015 review of studies on the subject (a study of studies, if you will). It found that pregnant women with depression who practiced prenatal yoga experienced a significant decrease in depression levels only when their practice included breath work, meditation or deep relaxation in addition to the physical exercise of performing poses.

And a pregnant woman’s stress levels and immune system may also benefit from prenatal yoga. A recent study looked at practitioners’ levels of cortisol, an indicator of stress, and immunoglobulin A, an indicator of immune function, from 16 to 36 weeks gestation, and found both measurements to be better (lower and higher, respectively) than those in pregnant women receiving only routine prenatal care during the same time period.

Reducing pain and stress and boosting immunity are big benefits for women who are restricted in which medications they can take for at least nine months.

Practitioners of the study’s prenatal yoga program began in the 26th week of pregnancy and continued through the 37th week. And they practiced a lot: Their regimen included three 60-minute supervised classes a week. In addition to poses, the classes included breath work, chanting, deep relaxation and other aspects often referred to as part of an “integrated” style of yoga.

For a different study, researchers asked pregnant women to perform 26 poses while monitoring their and their fetuses’ heart rates, among other vital signs. One of the poses tested, corpse pose, puts practitioners on their backs for a few minutes. The American College of Obstetricians and Gynecologists advises avoiding standing still or lying on your back for long periods of time, so the pose is sometimes questioned. So, too, is the popular downward-facing dog, also included in the study, because it’s a type of inversion.

But the study found no adverse effects on the women or fetuses for any of the poses. The study has some limitations, though. Its size is small — only 25 participants — and the average BMI of the participants, from the United States, was healthier than that of the average American pregnant woman. Still, the preliminary results are encouraging.

There are some general caveats to consider if you’re pregnant and interested in prenatal yoga. ACOG says exercise isn’t safe for pregnant women with certain conditions, so a conversation with health care providers prior to any class is warranted for everyone. ACOG also recommends avoiding “hot yoga” classes, which could cause you to overheat. Another thing to keep in mind: Ease into stretches. Hormones make ligaments and muscles looser during pregnancy, and overstretching could cause problems. And, as you can probably guess, poses that put you on your belly aren’t OK, except for perhaps early on in pregnancy.

Despite all those qualifiers, you’ll still find me — now at age 40, pregnant with my second child and a toddler to run after — on my yoga mat twice a week.

Laura Sanders is away on maternity leave. Emily Krieger is a freelance writer, editor and fact-checker in Seattle.

When it comes to raising kids, good advice and strong evidence can be hard to come by. The Growth Curve blog brings an accessible and metered approach to new studies and popular parenting topics. Growth Curve is a blog of Science News, which gives readers a concise overview of the most important science news from all fields and applications of science and technology.